Vehicular camera with lens heater

ABSTRACT

A camera for a vehicular vision system includes a housing and a lens barrel including a lens. The camera is configured to be disposed at an exterior portion of a vehicle so as to have a field of view exterior of the vehicle. A heating device is disposed at an exterior of the lens barrel. The heating device includes a thin foil heating element that at least partially circumscribes the lens barrel. The heating device includes an electrical lead that is configured to electrically connect to an electrical connector of the vehicle when the camera is disposed at the exterior portion of the vehicle. Responsive to a determination of current drawn by the heating device, a control of the camera determines the temperature at the lens and controls operation of the heating device based at least in part on the determined temperature.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a division of U.S. patent application Ser.No. 16/156,160, filed Oct. 10, 2018, now U.S. Pat. No. 10,761,319, whichclaims the filing benefits of U.S. provisional application Ser. No.62/571,949, filed Oct. 13, 2017, which is hereby incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to a vehicle vision system for avehicle and, more particularly, to a vehicle vision system that utilizesone or more cameras at a vehicle.

BACKGROUND OF THE INVENTION

Use of imaging sensors in vehicle imaging systems is common and known.Examples of such known systems are described in U.S. Pat. Nos.5,949,331; 5,670,935 and/or 5,550,677, which are hereby incorporatedherein by reference in their entireties.

Obscuring view by mud, salt or dust is becoming an increasing issue forvehicle cameras as their ability to determine and recognize objects canbe limited or interrupted. Vehicle manufacturers have recently startedto add washer nozzles mounted at the vehicle in close proximity to thecamera lens. These washer nozzles spray a high pressure stream of wateronto the lens when activated, thus cleaning the lens within a shortamount of time. Typically, the camera washer is integrated into theexisting windshield washer system and is activated through the samepump.

For some unique applications, a lens heating function may be includedwithin some cameras to defog the elements when needed. This function istypically very expensive and it is difficult to assemble the heatingelement inside of the camera. Such a heating function typically requiresan entirely different camera design that is larger and must haveadditional connection circuits. The production assembly processes wouldbe unique, more manually intensive and costly.

SUMMARY OF THE INVENTION

The present invention provides a vision system or imaging system for avehicle that utilizes one or more cameras (preferably one or more CMOScameras) to capture image data representative of images exterior of thevehicle, and provides a heating element to heat the lens of the camera,and optionally a lens washer attachment that provides pressurized fluidat the camera lens. The camera may be mounted or disposed at an exteriorstructure of the vehicle, such as, for example, a vehicle panel, grill,bumper, fascia, light bar, center high mounted stop lamp (CHMSL) or thelike, with its lens viewing exterior of the vehicle. The heating elementcomprises a thin resistive foil or strip that at least partiallycircumscribes the lens barrel.

These and other objects, advantages, purposes and features of thepresent invention will become apparent upon review of the followingspecification in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a vehicle with a vision system thatincorporates cameras in accordance with the present invention;

FIG. 2 is a perspective view of a camera and heater element inaccordance with the present invention;

FIG. 3 is a perspective view of another camera and heater element inaccordance with the present invention;

FIG. 4 is a schematic of a camera heating system of the presentinvention;

FIG. 5 is a schematic of another camera heating system of the presentinvention;

FIG. 6 is a schematic of another camera heating system of the presentinvention;

FIG. 7 is a schematic of another camera heating system of the presentinvention;

FIG. 8 is a schematic of another camera heating system of the presentinvention; and

FIG. 9 is a table showing various parameters associated with theexemplary system of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A vehicle vision system and/or driver assist system and/or objectdetection system and/or alert system operates to capture images exteriorof the vehicle and may process the captured image data to display imagesand to detect objects at or near the vehicle and in the predicted pathof the vehicle, such as to assist a driver of the vehicle in maneuveringthe vehicle in a rearward direction. The vision system includes an imageprocessor or image processing system that is operable to receive imagedata from one or more cameras and provide an output to a display devicefor displaying images representative of the captured image data.Optionally, the vision system may provide a top down or bird's eye orsurround view display and may provide a displayed image that isrepresentative of the subject vehicle, and optionally with the displayedimage being customized to at least partially correspond to the actualsubject vehicle.

Referring now to the drawings and the illustrative embodiments depictedtherein, a vehicle 10 includes an imaging system or vision system 12that includes at least one exterior facing imaging sensor or camera,such as a rearward facing imaging sensor or camera 14 a (and the systemmay optionally include multiple exterior facing imaging sensors orcameras, such as a forward facing camera 14 b at the front (or at thewindshield) of the vehicle, and a sideward/rearward facing camera 14 c,14 d at respective sides of the vehicle), which captures images exteriorof the vehicle, with the camera having a lens for focusing images at oronto an imaging array or imaging plane or imager of the camera (FIG. 1).The vision system 12 includes a control or electronic control unit (ECU)or processor 18 that is operable to process image data captured by thecameras and may provide displayed images at a display device 16 forviewing by the driver of the vehicle (although shown in FIG. 1 as beingpart of or incorporated in or at an interior rearview mirror assembly 20of the vehicle, the control and/or the display device may be disposedelsewhere at or in the vehicle). The data transfer or signalcommunication from the camera to the ECU may comprise any suitable dataor communication link, such as a vehicle network bus or the like of theequipped vehicle.

The cameras each include a housing and imager and a lens that isoriented such that the camera views exterior of the vehicle. Because thecamera is disposed at the vehicle exterior, such cameras are exposed tocold temperatures and temperature and humidity fluctuations, wherebymoisture and/or ice or snow may form or collect at the lens. Suchautomotive camera lenses are also susceptible to dirt or debriscollecting at the lens of the camera. This is particularly an issue forcameras mounted at the front of a vehicle, such as at a front bumper orgrill or fascia of the vehicle, or at the rear of the vehicle.

The camera includes a heater element, temperature sensor and smartheater driver. The heater can be turned on and may generate power up toabout 60 W and optionally up to about 90 W. The heater can help todevice or remove condensed water deposited on lens. The heater foil ismounted on the cylindrical lens holder (see FIGS. 2 and 3). Also, atemperature sensor can be integrated with the heater foil element tosense the temperature at the lens. Optionally, in order to measuretemperature in case the temperature sensor is broken (or not included),the camera and system can measure or determine the current being drawnby the heater element and can estimate the temperature at the lens basedon the current level and power consumption of the heater element. Also,the heater element can help to meet power requirements for Power overCoax (POC) cameras (see FIG. 8).

This camera may optionally also include a fluid spraying device thatconnects to a pressurized fluid supply and has a fluid passageway andnozzle so as to spray fluid onto the lens to clean the lens of dirt ordebris. The spraying or cleaning device may operate with or separatefrom the heating device.

Thus, the heating device of the present invention comprises a foilheating element that is disposed around the lens barrel of the exteriorvehicle camera, whereby the foil heating element at least partiallycircumscribes the lens barrel so as to heat the lens barrel (and lensoptics disposed therein) when the heating device is powered. Thediagrams of FIGS. 4-7 show different options to control the heatingelement. For example, the diagrams of FIGS. 4, 6 and 7 show use of atemperature sensor at the camera, while the diagram of FIG. 5 showstemperature determination or estimation via sensing the current flowingthrough the heater element.

FIG. 8 shows the camera connected to the ECU via a coaxial cableconnection. At power up and prior to the camera load being active, thecurrent draw across the coaxial cable will be very low, resulting inminimal total line voltage drop. The max “open circuit” voltage from theECU is selected or specified to ensure that the camera power managementhas sufficient voltage rating. The power over coax heater may provide amaximum camera wattage of about 6.8 Watts (power consumption of all ofthe integrated circuits from the Vout2 supply in FIG. 8), with the inputvoltage at the camera (Vin2) being about 22 volts (the minimum operatingvoltage, which impacts the coaxial cable current and inductor sizes).Various parameters associated with an exemplary system as shown in FIG.8 are shown in the table of FIG. 9.

The heater is operable to device the camera lens by heating to 70degrees C. (or less) so that the heater can device a 0.44 mm thick layerof ice on the lens within 30 seconds at an ambient temperature as low as−40 degrees C. The heater may achieve this with a maximum powerconsumption of about 10 Watts. The camera lens holder and lens retainermay comprise a plastic structure or a metallic structure (such as analuminum or copper lens holder), depending on the particular applicationand desired heating (based on the thermal conductivity of the materials)of the lens via the heater foil wrapped at least partially around thelens holder.

For example, the lens may have a diameter of 12-15 mm, with an outerglass lens element or optic, and glass or polymer inner lens elements oroptics, with the lens retainer comprising aluminum and the lens barrelcomprising plastic. The heater operates to melt a 0.5 mm thick ice layerwithin about 30 seconds, with the heater activation voltage being 10V+/−0.25 V and deactivation being when the voltage drops below that orwhen the temperature at the lens reaches about 65 degrees C. Preferably,this can be achieved at ambient temperatures as low as about −40 degreesC. The parameters of the camera and heater may be selected based on whatmaterials and dimensions achieve the desired heating results (time andtemperature).

The heating element may comprise a heater foil with aluminum tape, whichhas a maximum power of about 4 W at about 12 V. A smart switch (toactivate/deactivate the heater) may be used that provides statusfeedback. The heater may be operated via PWM control. Optionally, theheater may be controlled (activated, deactivated) without a temperaturemeasurement, but using an estimation of the ambient temperature and theknown power consumption, which may be calculated based on the heaterresistance, battery voltage and PWM duty cycle.

The heater power consumption required to melt ice from the lens may bedetermined by calculating the energies it takes to change thetemperature of each element (aluminum, glass, ice) from the coldesttemperature of −40 degrees C. to 1 degree C. (delta of 41), and summingthose energies, which are about 19 J (aluminum), 66 J (glass), 71 J(ice/water), and 280 J (melting), and total about 436 J. Thus, in orderto generate 436 J in 30 seconds (the desired melting time), the heaterpower consumption will be about 14.5 W (436 J/30 s). In addition, therewould be some heat transfer between the heater and the lens over airgaps, and heat dissipation to the remaining lens parts (barrel, otheroptics, spacers, etc.).

The heating elements or circuits could be directly attached to a vehicleharness or be integrated into a camera pigtail if included in thedesign. Activation and control of the heating element may be viamessages from the camera to the vehicle's communications network.Control could also be included in this device by way of integratedtemperature sensor and timer. For example, a temperature sensor may beincluded at the camera or heater element such that, when the sensedtemperature drops below a threshold temperature, the heating device isautomatically activated to heat the lens barrel to limit or precludemoisture or ice forming on the lens optics.

Thus, the present invention provides a heating system (and optionally awasher system too) that can be attached at a camera (such as at and atleast partially or entirely around a lens barrel of the camera) forheating the lens. The heating system and/or washer system thus may beselected for and added to a vehicle camera, depending on the applicationof the camera, without any modifications to the camera itself.

The camera may utilize aspects of the cameras described in U.S.Publication Nos. US-2018-0207691; US-2016-0272163 and/orUS-2016-0264064, which are hereby incorporated herein by reference intheir entireties.

The camera or sensor may comprise any suitable camera or sensor.Optionally, the camera may comprise a “smart camera” that includes theimaging sensor array and associated circuitry and image processingcircuitry and electrical connectors and the like as part of a cameramodule, such as by utilizing aspects of the vision systems described inInternational Publication Nos. WO 2013/081984 and/or WO 2013/081985,which are hereby incorporated herein by reference in their entireties.

The system includes an image processor operable to process image datacaptured by the camera or cameras, such as for detecting objects orother vehicles or pedestrians or the like in the field of view of one ormore of the cameras. For example, the image processor may comprise animage processing chip selected from the EYEQ™ family of image processingchips available from Mobileye Vision Technologies Ltd. of Jerusalem,Israel, and may include object detection software (such as the typesdescribed in U.S. Pat. Nos. 7,855,755; 7,720,580 and/or 7,038,577, whichare hereby incorporated herein by reference in their entireties), andmay analyze image data to detect vehicles and/or other objects.Responsive to such image processing, and when an object or other vehicleis detected, the system may generate an alert to the driver of thevehicle and/or may generate an overlay at the displayed image tohighlight or enhance display of the detected object or vehicle, in orderto enhance the driver's awareness of the detected object or vehicle orhazardous condition during a driving maneuver of the equipped vehicle.

For example, the vision system and/or processing and/or camera and/orcircuitry may utilize aspects described in U.S. Pat. Nos. 8,694,224;7,005,974; 5,760,962; 5,877,897; 5,796,094; 5,949,331; 6,222,447;6,302,545; 6,396,397; 6,498,620; 6,523,964; 6,611,202; 6,201,642;6,690,268; 6,717,610; 6,757,109; 6,802,617; 6,806,452; 6,822,563;6,891,563; 6,946,978; 7,859,565; 5,550,677; 5,670,935; 6,636,258;7,145,519; 7,161,616; 7,230,640; 7,248,283; 7,295,229; 7,301,466;7,592,928; 7,881,496; 7,720,580; 7,038,577; 6,882,287; 5,929,786 and/or5,786,772, which are all hereby incorporated herein by reference intheir entireties. The system may communicate with other communicationsystems via any suitable means, such as by utilizing aspects of thesystems described in International Publication Nos. WO 2010/144900; WO2013/043661 and/or WO 2013/081985, and/or U.S. Publication No.US-2012-0062743, which are hereby incorporated herein by reference intheir entireties.

Changes and modifications in the specifically described embodiments canbe carried out without departing from the principles of the invention,which is intended to be limited only by the scope of the appendedclaims, as interpreted according to the principles of patent lawincluding the doctrine of equivalents.

1. A camera for a vehicular vision system, said camera comprising: acamera housing; a lens barrel including a lens having lens opticsdisposed in said lens barrel, wherein said lens barrel is attached atsaid camera housing so that said lens is optically aligned with animager disposed in said camera housing; wherein said camera isconfigured to be disposed at an exterior portion of a vehicle so as tohave a field of view exterior of the vehicle; a heating device disposedat an exterior of said lens barrel, said heating device comprising athin foil heating element that at least partially circumscribes saidlens barrel; a control that controls operation of said heating deviceresponsive at least in part to temperature at said lens; wherein saidheating device includes an electrical lead that is configured toelectrically connect to an electrical connector of the vehicle when saidcamera is disposed at the exterior portion of the vehicle; and wherein,with said camera disposed at the exterior portion of the vehicle andwith said electrical lead electrically connected to the electricalconnector of the vehicle, and responsive to a determination of currentdrawn by said heating device, said control estimates the temperature atsaid lens, and wherein said control controls operation of said heatingdevice based at least in part on the estimated temperature.
 2. Thecamera of claim 1, wherein, responsive to determination that theestimated temperature at said lens is below a threshold temperature,said control operates said heating device to increase the temperature ofsaid lens barrel of said camera.
 3. The camera of claim 1, wherein saidcontrol deenergizes said heating device responsive to determination thata threshold time period following energization of said heating devicehas elapsed.
 4. The camera of claim 1, wherein said control deenergizessaid heating device responsive to determination that a power consumptionof said heating device reaches a threshold level.
 5. The camera of claim1, wherein said control deenergizes said heating device responsive todetermination that the estimated temperature at said lens is at or abovea threshold temperature.
 6. The camera of claim 1, comprising a washerhaving a connector and fluid passageway, and wherein said connector,with said camera disposed at the exterior portion of the vehicle, isconnected to a washer system of the vehicle such that, when the vehiclewasher system is actuated, pressurized fluid flows through said fluidpassageway and onto said lens.
 7. The camera of claim 1, wherein saidcamera is configured to be fixedly mounted at the exterior portion ofthe vehicle.
 8. The camera of claim 7, wherein, with said camera fixedlymounted at the exterior portion of the vehicle, said lens is exposed atthe exterior portion of the vehicle.
 9. The camera of claim 1,comprising a temperature sensor for sensing a temperature at saidcamera, wherein, with said camera disposed at the exterior portion ofthe vehicle and with said electrical lead electrically connected to theelectrical connector of the vehicle, and responsive to an output of saidtemperature sensor that is indicative of the temperature at said camerabeing below a threshold level, said control operates said heating deviceto increase the temperature of said lens barrel of said camera.
 10. Thecamera of claim 1, wherein, with said camera disposed at the exteriorportion of the vehicle and with said electrical lead electricallyconnected to the electrical connector of the vehicle, said controlenergizes said heating device responsive to determination that anambient temperature is below a threshold temperature.
 11. The camera ofclaim 1, wherein said heating device, when said camera is disposed atthe exterior portion of the vehicle and when said heating device iselectrically powered, heats said lens barrel and the lens opticsdisposed therein.
 12. A camera for a vehicular vision system, saidcamera comprising: a camera housing; a lens barrel including a lenshaving lens optics disposed in said lens barrel, wherein said lensbarrel is attached at said camera housing so that said lens is opticallyaligned with an imager disposed in said camera housing; wherein saidcamera is configured to be disposed at an exterior portion of a vehicleso as to have a field of view exterior of the vehicle; a heating devicedisposed at an exterior of said lens barrel, said heating devicecomprising a thin foil heating element that at least partiallycircumscribes said lens barrel; a control that controls operation ofsaid heating device responsive at least in part to temperature at saidlens; wherein said heating device includes an electrical lead that isconfigured to electrically connect to an electrical connector of thevehicle when said camera is disposed at the exterior portion of thevehicle; wherein, with said camera disposed at the exterior portion ofthe vehicle and with said electrical lead electrically connected to theelectrical connector of the vehicle, said control energizes said heatingdevice responsive to determination that an ambient temperature is belowa threshold temperature; wherein, with said camera disposed at theexterior portion of the vehicle and with said electrical leadelectrically connected to the electrical connector of the vehicle, andresponsive to a determination of current drawn by said heating devicewhen said heating device is energized, said control determines thetemperature at said lens; wherein, responsive to the determinedtemperature at said lens being below a first threshold temperature, saidcontrol operates said heating device to increase the temperature of saidlens barrel of said camera; and wherein said control deenergizes saidheating device responsive at least in part to determination that thedetermined temperature at said lens is at or above a second thresholdtemperature that is greater than the first threshold temperature. 13.The camera of claim 12, wherein said control deenergizes said heatingdevice responsive to determination that a threshold time periodfollowing energization of said heating device has elapsed.
 14. Thecamera of claim 12, wherein said control deenergizes said heating deviceresponsive to determination that a power consumption of said heatingdevice reaches a threshold level.
 15. The camera of claim 12, whereinsaid control energizes said heating device responsive to determinationthat an ambient temperature is below a threshold temperature.
 16. Thecamera of claim 12, comprising a temperature sensor for sensing atemperature at said camera, wherein, with said camera disposed at theexterior portion of the vehicle and with said electrical leadelectrically connected to the electrical connector of the vehicle, andresponsive to an output of said temperature sensor that is indicative ofthe temperature at said camera being below a threshold level, saidcontrol operates said heating device to increase the temperature of saidlens barrel of said camera.
 17. A camera for a vehicular vision system,said camera comprising: a camera housing; a lens barrel including a lenshaving lens optics disposed in said lens barrel, wherein said lensbarrel is attached at said camera housing so that said lens is opticallyaligned with an imager disposed in said camera housing; wherein saidcamera is configured to be disposed at an exterior portion of a vehicleso as to have a field of view exterior of the vehicle; a heating devicedisposed at an exterior of said lens barrel, said heating devicecomprising a thin foil heating element that at least partiallycircumscribes said lens barrel; a control that controls operation ofsaid heating device responsive at least in part to temperature at saidlens; wherein said heating device includes an electrical lead that isconfigured to electrically connect to an electrical connector of thevehicle when said camera is disposed at the exterior portion of thevehicle; wherein, with said camera disposed at the exterior portion ofthe vehicle and with said electrical lead electrically connected to theelectrical connector of the vehicle, said control energizes said heatingdevice responsive to determination that an ambient temperature is belowa threshold temperature; wherein, with said camera disposed at theexterior portion of the vehicle and with said electrical leadelectrically connected to the electrical connector of the vehicle, andresponsive to a determination of current drawn by said heating devicewhen said heating device is energized, said control determines thetemperature at said lens, and wherein said control controls operation ofsaid heating device based at least in part on the determinedtemperature; and wherein said control deenergizes said heating deviceresponsive to determination that a threshold time period followingenergization of said heating device has elapsed.
 18. The camera of claim17, wherein, responsive to determination that the temperature at saidlens is below a threshold temperature, said control operates saidheating device to increase the temperature of said lens barrel of saidcamera.
 19. The camera of claim 17, wherein said control deenergizessaid heating device responsive to determination that the temperature atsaid lens is at or above a threshold temperature.
 20. The camera ofclaim 17, wherein said control deenergizes said heating deviceresponsive to determination that a power consumption of said heatingdevice reaches a threshold level.